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Sample Preparation Visual Observations
Preparing the Sample Onset Point
Careless sample preparation is the leading cause of The onset point, also called the collapse point, is considered
inaccurate and irreproducible results. Substances must the start of the melt. Liquid clearly appears for the first time
be fully dry, homogeneous and in fine powdered as a separate phase in coexistence with the crystals. The
form. Moist samples must be dried first. Coarse crystalline sample has changed appearance and collapsed away from
and non-homogeneous samples must be crushed in |